twangster probably summed it correctly and neither the Canal or Royal are telling anyone.  What I do know is the maximum permitted air draft on a case by case basis is 205' at low tide.  The BoA has a clearance of 201' at Mean High Water (MHW).   The tides at Balboa can vary over 20' between high and low tides, during any given month there are a large number of days were tidal range will be between 13-17'.  There are a few days where the tidal range will only be around a 8' swing between low and